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PCM1808: What's the testing environment of SNR

Wiky Liao
Intellectual 1970 points
Part Number: PCM1808


Hi Team,

May I know the PCM1808 testing environment of SNR? Such as analog input level / test schematic? We know other environment are listed at top of datasheet, but still missing input level / test schematic info.

Our customer using PCM1808 in project and the SNR only have 93dB, changing input level we may even get 86dB. So we wonder the exact testing of PCM1808. thanks.

  • 0
    TI__Mastermind 23050 points

    Hi Wiky,

    Are you testing on an EVM or in the customer system. If you can share the schematic I'd be happy to review it. If you're measuring 93dB as the noise floor though then I suspect that there is a mismatch in the data formats being used because this is 6dB from the expected value, which suggests the MSB is shifted. SNR is measured by comparing 0dBFS full scale level to the noise floor with the inputs AC coupled to GND. A-weighting will also result in a few dB of difference in the measurement so you may also want to check if you have the a-weighting filter enabled.

    Best,

    Zak